Suppose that y varies directly with x, and y=3 when x=8 (a) Write an inverse equation equation that relates Equation: (b) Find y when x=4

Question

asked Apr 8, 2019 215k views

1 Answer

Dmoebius · Answer 1 · 2019-04-15T05:06:42+0000

we are given

y varies directly with x

so, we can write equation as

y=kx

where

k is a constant

now, we need to find k

we are given

y=3 when x=8

so, we can plug it and find k

3=k*8

k=(3)/(8)

now, we can plug it back

y=(3)/(8)x

(A)

we have got equation as

y=(3)/(8)x

for finding inverse , we can switch x and y

x=(3)/(8)y

now, we can solve for y

8*x=8*(3)/(8)y

8*x=3y

f^(-1)(x)=(8x)/(3) ............Answer

(B)

we have

y=(3)/(8)x

we can plug x=4 and find y

y=(3)/(8)*4

y=(3)/(2) ................Answer